root@mautic:~# ee site update mautic.agencialoud.com --letsencrypt
Letsencrypt is currently in beta phase.
Do you wish to enable SSl now for mautic.agencialoud.com?
Type "y" to continue [n]:y
Please Wait while we fetch SSL Certificate for your site.
It may take time depending upon network.
Unable to setup, Let's Encrypt
Please make sure that your site is pointed to
same server on which you are running Let's Encrypt Client
to allow it to verify the site automatically.

I also looked for solutions in many places, followed several suggestions but without any success

I created two A records into my zone editor to point the EasyEngine app as subdomain (mautic) as we can see

A RECORDS:

mautic.agencialoud.com. 14400 IN A 159.203.176.69
www.mautic.agencialoud.com. 14400 IN A 159.203.176.69